A film with an ASA speed rating of 200 is how many times faster than one with a rating of 50?

In the context of photography, the ASA (American Standards Association) speed rating indicates the sensitivity of film to light. A higher ASA number suggests greater sensitivity, allowing you to capture images in lower light conditions or reduce exposure time.

To determine how many times faster a film with an ASA rating of 200 is compared to one rated at 50, we compare their sensitivity levels. The speed rating of 200 is 200, while the speed rating of 50 is 50. To find the speed difference, you divide the higher ASA value by the lower ASA value:

200 ÷ 50 = 4.

This calculation means that the film rated at 200 is four times more sensitive, or "faster," than the film rated at 50. Thus, when considering exposure conditions, a 200 ASA film will require 1/4 of the light that a 50 ASA film would need to achieve the same exposure level.